Han, D. et al. Science 339, 1412–1415 (2013).

A wide variety of DNA nanostructures, ranging from the merely cute to the cleverly useful, have been made using so-called DNA origami folding techniques. However, it has remained a challenge to build gridiron-like structures using the DNA origami approach, in which a long scaffold strand is folded by interactions with many 'staple' strands. Han et al. now describe a design approach that utilizes a set of immobile four-arm Holliday junction analogs as the basic structural unit to create gridiron nanostructures. They further show that by adding DNA segments of different lengths between the individual joints, they could create a variety of two- and three-dimensional nanostructures, from simple lattices to multilayer gridirons to wire-frame spheres and screws.